Intelligently modifying the gain parameter of a playback device

ABSTRACT

Techniques for optimizing a player based on the addition of a second player are disclosed. In an embodiment, when a first player no longer needs to play certain audio frequencies due to the addition of a second player, the gain of the first player is automatically increased as part of the setup process. In another embodiment, when a first player needs to play certain audio frequencies, for example due to the removal of a second player, the gain of the first player is automatically decreased. Many other embodiments are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 13/458,558 filed on Apr. 27, 2012, the entire contents of whichare hereby incorporated by reference.

BACKGROUND

The presently described technology is directed towards technology foruse in the area of consumer electronics. In particular, certainembodiments described herein are directed to intelligently increasingthe sound level of a player when combined to play with another player.

Music is very much a part of our everyday lives. And thanks to theadvancement of technology, music content is now more accessible thanever. The same can be said of other types of media, such as television,movies, and other audio and video content. In fact, now a user canreadily access content over the Internet through an online store, anInternet radio station, online music service, online movie service, andthe like, in addition to the more traditional means of accessing audioand video content.

The demand for such audio and video content continues to surge. Giventhe high demand over the years, technology used to access and play suchcontent has likewise improved. Even still, technology used in accessingthe content and/or the playback of such content can be significantlyimproved or developed in ways that the market or end users do notanticipate.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, aspects, and advantages of the presently described technologywill become better understood by a person skilled in the art with regardto the following description, appended claims, and accompanying drawingswhere:

FIG. 1 shows an example configuration in which certain embodiments maybe practiced;

FIG. 2A shows an illustration of an example zone player having abuilt-in amplifier and speakers;

FIG. 2B shows an illustration of an example zone player having abuilt-in amplifier and connected to external speakers;

FIG. 2C shows an illustration of an example zone player connected to anA/V receiver and speakers;

FIG. 3 shows an illustration of an example controller;

FIG. 4 shows an internal functional block diagram of an example zoneplayer;

FIG. 5 shows an internal functional block diagram of an examplecontroller;

FIG. 6 shows an illustration of an example zone player;

FIG. 7 shows an illustration of the example zone player in FIG. 6, butwith the addition of a second zone player; and

FIG. 8 shows a flowchart illustrating an example method forintelligently adjusting a sound level of a first player when combined toplay with a second player.

DETAILED DESCRIPTION I. Overview

The embodiments described herein relate to new technology for increasingthe sound level of a player by an automatic configuration adjustmentwhen combined to play, or not play, with another audio output device.The embodiments are particularly useful in a loudspeaker system in whichan audio output device, like a subwoofer, is added or removed. Theembodiments may also find utility, for example, in connection with anyenvironment and audio system for which an increased sound level isdesired.

In an embodiment, for example, an audio signal is received that containsa range of audio frequencies. The audio signal may be an analog ordigital representation of sound. The range of audio frequencies mightinclude 20 to 20,000 Hz, for example, or some other range (small orlarge) audible to the average human. The audio signal is amplifiedaccording to a gain parameter. The gain parameter may be stored inmemory or some other storage medium. The gain parameter is increasedresponsive to a determination that no more than a portion of the rangeof audio frequencies is to be reproduced. The audio signal, containing aportion of the range of audio frequencies, is amplified according to thehigher gain parameter.

In another embodiment, for example, a high-pass filter is applied to afull-range audio signal. In some embodiments, the high-pass filer isapplied to the full-range audio signal at the player. In alternativeembodiments, the high-pass filter is applied before the signal reachesthe player. Irrespective of where the signal filtering occurs, it may bedetermined, such as during zone setup or configuration, that only aportion of the range of audio frequencies is to be reproduced by theplayer, such as the mid and high frequencies. The bass frequencies maybe sent to a subwoofer player. The crossover frequency may be determinedbased on the player characteristics. With the high pass filter beingapplied, the maximum sound pressure level (SPL) capability of the playercan be greater. To utilize the potential increase in output capability,the amplifier gain of the player is automatically increased. Theadjustment of SPL may be reflected in the loudness or volume output ofthe player, the zone for which the player is a part of, or both.

In another embodiment, for example, a user can pair a subwoofer withanother player or players over a wireless network. The subwoofer may bededicated to the reproduction of low audio frequencies (sometimesreferred to as “bass”). The subwoofer can augment the low frequencyrange of the player(s) covering the mid to high frequency bands. Using acontroller, such as described below, the pairing initiates a process forautomatically adjusting the performance of the player or players, and insome embodiments adjusts the performance of the subwoofer, if thesubwoofer is so programmed.

In some embodiments, a gain parameter may be automatically decreasedback to a previous gain setting when it is determined that the player isconfigured to handle a wider bandwidth signal (e.g., when a subwoofer isremoved from the system). For example, the gain setting of the playermay dynamically switch to different setting levels based on the setup ofthe player with additional players in a particular zone or zones or theremoval of players from the particular zone or zones.

In some embodiments, gain parameters, including the higher gainparameter, are stored in memory or storage medium at the player.Accordingly, the gain parameters may be accessed when a dynamic switchfrom one gain parameter to another gain parameter is to occur. More thantwo gain parameters may be stored, such as in a table of gainparameters, where each gain parameter corresponds to a particular setup.

In some embodiments, the gain parameter is stored in memory or storagemedium and the higher (and in some cases, the lower) gain parameter isdetermined in real-time. Accordingly, the gain new gain parameter iscomputed or determined responsive to setup of the system or some otherdynamic event. In some embodiments, the gain parameters may be computedby a device separate from the player and subsequently sent to theplayer.

In some embodiments, any of three actions can trigger an SPL change:zone players are bonded (e.g., paired) or removed from a bonded zone, aconfiguration change is made in the user interface (e.g., the userselects/deselects a “sub” option), and based on the content (e.g., theSPL of the midrange may be increased with 2.1 audio which includesstereo left and right channels and a low-frequency channel, but not withjust 2-channel audio which only includes stereo left and rightchannels).

The description discloses example systems, methods, apparatus, andarticles of manufacture including, among other components, firmwareand/or software executed on hardware. It should be noted that suchsystems, methods, apparatus, and/or articles of manufacture are merelyillustrative and should not be considered as limiting. For example, itis contemplated that any or all of these firmware, hardware, and/orsoftware components could be embodied exclusively in hardware,exclusively in software, exclusively in firmware, or in any combinationof hardware, software, and/or firmware. Accordingly, while the followingdescribes example systems, methods, apparatus, and/or articles ofmanufacture, the examples provided are not the only way(s) to implementsuch systems, methods, apparatus, and/or articles of manufacture.

When any of the appended claims are read to cover a purely softwareand/or firmware implementation, at least one of the elements in at leastone example is hereby expressly defined to include a tangible mediumsuch as a memory, DVD, CD, Blu-ray, and so on, storing the softwareand/or firmware.

Furthermore, reference herein to “embodiment” means that a particularfeature, structure, or characteristic described in connection with theembodiment can be included in at least one example embodiment of theinvention. The appearances of this phrase in various places in thespecification are not necessarily all referring to the same embodiment,nor are separate or alternative embodiments mutually exclusive of otherembodiments. As such, the embodiments described herein, explicitly andimplicitly understood by one skilled in the art, can be combined withother embodiments.

II. Example Environment

Referring now to the drawings, in which like numerals may refer to likeparts throughout the figures. FIG. 1 shows an example systemconfiguration 100 in which certain embodiments described herein may bepracticed. By way of illustration, the system configuration 100represents a home with multiple zones. Each zone, for example,represents a different room or space, such as an office, bathroom,bedroom, kitchen, dining room, family room, home theater room, utilityor laundry room, and patio. While not shown here, a single zone maycover more than one room or space. One or more of the zone players 102to 124 are shown in each respective zone. A controller 130 (e.g., shownin the kitchen for purposes of illustration) provides control to thesystem configuration 100. It is understood that multiple controllers mayoperate in system configuration 100, and each controller may be used,for example, to control any zone player or group of zone players or asubset of zone players or group of zone players. The systemconfiguration 100 illustrates an example whole house audio system,though it is understood that the technology described herein is notlimited to its particular place of application or to an expansive systemlike a whole house audio system.

FIGS. 2A, 2B, and 2C show example illustrations of a zone player 200.The zone player 200 may correspond to any of zone players 102 to 124.With respect to FIG. 2A, the example zone player 200 includes a built-inamplifier to power speakers 202. A particular speaker might include atweeter, mid-range driver, or subwoofer. In certain embodiments, thezone player 200 of FIG. 2A may be configured to play stereophonic audioor monaural audio. With respect to FIG. 2B, the example zone player 200includes a built-in amplifier to power a set of detached speakers 204.Speakers 204 might include any type of loudspeaker. With respect to FIG.2C, the example zone player 200 does not include an amplifier, butallows a receiver 206, or another audio and/or video type device withbuilt-in amplification, to connect to a data network 128 and play audioreceived over the data network 128 via receiver 206 and speakers 204.Example zone players include a “PLAY:5”, “PLAY:3”, “CONNECT”, and“CONNECT:AMP,” which are offered by Sonos, Inc. of Santa Barbara, Calif.A zone player may also be referred to herein as a “playback device” or a“player”, and a zone player is not limited to the particular examplesillustrated in FIGS. 2A, 2B, and 2C. For example, a zone player mayinclude a wired or wireless headphone. In another example, a zone playermight include a subwoofer. In yet another example, a zone player mightinclude a television.

FIG. 3 shows an example illustration of a wireless controller 300 in adocking station 302. The controller 300 may correspond to thecontrolling device 130 of FIG. 1. The controller 300 is provided with atouch screen 304 that allows a user to interact with the controller 300,for example, to retrieve and navigate a playlist of audio items, controloperations of one or more zone players, and provide overall control ofthe system configuration 100. In certain embodiments, any number ofcontrollers may be used to control the system configuration 100. Thecontrollers might be wireless like wireless controller 300 or wired tothe data network 128. Furthermore, an application running on anynetwork-enabled portable devices, such as an iPhone, iPad, Androidpowered phone, or any other smart phone or network-enabled device may beused as a controller by connecting to the data network 128 and/ordirectly to one or more zone players 102 to 124 or to some otherconfigured device in system configuration 100. An application running ona laptop or desktop PC or Mac may also be used as a controller. Examplecontrollers include a “Sonos CONTROL”, “Sonos Controller CR100,” “SonosController for iPhone,” “Sonos Controller for iPad,” “Sonos Controllerfor Android”, “Sonos Controller for Mac or Pc,” which are offered bySonos, Inc. of Santa Barbara, Calif. Those skilled in the art willappreciate the flexibility of such an application and its ability to beported to a new type of portable device.

Referring back to the system configuration 100 of FIG. 1, a particularzone may contain one or more zone players. For example, the family roomcontains two zone players 106 and 108, while the kitchen is shown withone zone player 102. Zones may be dynamically configured by positioninga zone player in a room or space and assigning via the controller 130the zone player to a new or existing zone. As such, zones may becreated, combined with another zone, removed, and given a specific name(e.g., “Kitchen”), if so programmed. The zone players 102 to 124 arecoupled directly or indirectly to a data network, represented in thefigure by 128. The data network 128 is represented by an octagon in thefigure to stand out from other components shown in the figure. While thedata network 128 is shown in a single location, it is understood thatsuch a network may be distributed in and around the system configuration100.

Particularly, the data network 128 may be a wired network, a wirelessnetwork, or a combination of both. In one example, one or more of thezone players 102 to 124 are wirelessly coupled to the data network 128based on a proprietary mesh network. In another example, one or more ofthe zone players 102 to 124 are wirelessly coupled to the data network128 using a non-mesh topology. In yet another example, one or more ofthe zone players 102 to 124 are coupled via a wire to the data network128 using Ethernet or similar technology. In addition to the one or morezone players 102 to 124 connecting to the data network 128, the datanetwork 128 may further allow access to a wide area network, such as theInternet.

In certain embodiments, the data network 128 may be created byconnecting any of zone players 102 to 124, or some other connectingdevice, to a broadband router. Other zone players 102 to 124 may then beadded wired or wirelessly to the data network 128. For example, a zoneplayer (e.g., any of zone players 102 to 124) may be added to the systemconfiguration 100 by simply pressing a button on the zone player itself,which enables a connection to be made to the data network 128. Thebroadband router may be connected to an Internet Service Provider (ISP),for example. The broadband router may be used to form another datanetwork within the system configuration 100, which may be used in otherapplications (e.g., web surfing). The data network 128 may also be usedin other applications, if so programmed. Further, in certainembodiments, the data network 128 is the same network used for otherapplications in the household, for example.

In certain embodiments, each zone can play from the same audio source asanother zone or each zone can play from a different audio source. Forexample, someone can be grilling on the patio and listening to jazzmusic via zone player 124, while someone is preparing food in thekitchen and listening to classical music via zone player 102. Further,someone can be in the office listening to the same jazz music via zoneplayer 110 that is playing on the patio via zone player 124. In someembodiments, the jazz music played via zone players 110 and 124 isplayed in synchrony. Synchronizing playback amongst zones allows forsomeone to pass through zones while seamlessly listening to the audio.Further, zones may be put into a “party mode” such that all associatedzones will play audio in synchrony.

In certain embodiments, a zone contains two or more zone players. Forexample, the family room contains two zone players 106 and 108, and thehome theater room contains at least zone players 116, 118, and 120. Azone may be configured to contain as many zone players as desired, andfor example, the home theater room might contain additional zone playersto play audio from a 5.1 channel or greater audio source (e.g., a movieencoded with 5.1 or greater audio channels). If a zone contains two ormore zone players, such as the two zone players 106 and 108 in thefamily room, then the two zone players 106 and 108 may be configured toplay the same audio source in synchrony, or the two zone players 106 and108 may be paired to play two separate sounds in left and rightchannels, for example. In other words, the stereo effects of a sound maybe reproduced or enhanced through the two zone players 106 and 108, onefor the left sound and the other for the right sound. In certainembodiments, paired zone players may play audio in synchrony with otherzone players. A zone with paired players may also be referred to as a“bonded zone.”

In certain embodiments, three or more zone players may be configured toplay various channels of audio that is encoded with three channels ormore sound. For example, the home theater room shows zone players 116,118, and 120. If the sound is encoded as 2.1 channel audio, then thezone player 116 may be configured to play left channel audio, the zoneplayer 118 may be configured to play right channel audio, and the zoneplayer 120 may be configured to play bass frequencies. Otherconfigurations are possible and depend on the number of zone players andthe type of audio. Further, a particular zone may be configured to playa 5.1 channel audio in one instance, such as when playing audio from amovie, and then dynamically switch to play stereo, such as when playingaudio from a two channel source.

In certain embodiments, two or more zone players may be sonicallyconsolidated to form a single, consolidated zone player. A consolidatedzone player (though comprised of multiple, separate devices) may beconfigured to process and reproduce sound differently than anunconsolidated zone player or zone players that are paired, because aconsolidated zone player will have additional speaker drivers from whichsound may be passed. The consolidated zone player may further be pairedwith a single zone player or yet another consolidated zone player. Eachplayback device of a consolidated playback device is preferably set in aconsolidated mode.

According to some embodiments, one can continue to do any of: group,consolidate, and pair zone players until a desired configuration iscomplete. The actions of grouping, consolidation, and pairing arepreferably performed through a control interface, such as usingcontroller 130, and not by physically connecting and re-connectingspeaker wire, for example, to individual, discrete speakers to createdifferent configurations. As such, certain embodiments described hereinprovide a more flexible and dynamic platform through which soundreproduction can be offered to the end-user.

Sources of audio content to be played by zone players 102 to 124 arenumerous. Music from a personal library stored on a computer ornetworked-attached storage (NAS) may be accessed via the data network128 and played. Internet radio stations, shows, and podcasts may beaccessed via the data network 128. Music services that let a user streamand download music and audio content may be accessed via the datanetwork 128. Further, music may be obtained from traditional sources,such as a turntable or CD player, via a line-in connection to a zoneplayer, for example. Audio content may also be accessed through AirPlay™wireless technology by Apple, Inc. Audio content received from one ormore sources may be shared amongst the zone players 102 to 124 via thedata network 128 and controller 130.

III. Example Playback Device

Referring now to FIG. 4, there is shown an example functional blockdiagram of a zone player 400 in accordance with an embodiment. The zoneplayer 400 contains a network interface 402, a processor 408, a memory410, an audio processing component 412, a module 414, an audio amplifier416, and a speaker unit 418 connected to the audio amplifier 416. FIG.2A shows an example illustration of the front side of such a zoneplayer. Other types of zone players may not include the speaker unit 418(e.g., such as shown in FIG. 2B) or the audio amplifier 416 (e.g., suchas shown in FIG. 2C). Further, it is contemplated that the zone player400 may be integrated into another component. For example, the zoneplayer 400 could be constructed as part of a lamp for indoor or outdooruse. Additionally it is understood that the zone player 400 could beconstructed as part of a video reproducing device such as a televisionor some other device that reproduces sound

Referring back to FIG. 4, the network interface 402 facilitates a dataflow between zone players and other devices on a data network (e.g., thedata network 128 of FIG. 1) and the zone player 400. In someembodiments, the network interface 402 may manage the assembling of anaudio source or file into smaller packets that are to be transmittedover the data network or reassembles received packets into the originalsource or file. In some embodiments, the network interface 402 mayfurther handle the address part of each packet so that it gets to theright destination or intercepts packets destined for the zone player400. Accordingly, in certain embodiments, each of the packets includesan IP-based source address as well as an IP-based destination address.

In certain embodiments, the network interface 402 may include one orboth of a wireless interface 404 and a wired interface 406. The wirelessinterface 404, also referred to as an RF interface, provides networkinterface functions for the zone player 400 to wirelessly communicatewith other devices in accordance with a communication protocol (e.g.,any of the wireless standards IEEE 802.11a, 802.11b, 802.11g, 802.11n,or 802.15). The wired interface 406 provides network interface functionsfor the zone player 400 to communicate over a wire with other devices inaccordance with a communication protocol (e.g., IEEE 802.3 or IEEE1901). In some embodiments, a zone player includes both of theinterfaces 404 and 406. In some embodiments, a zone player 400 includesonly the wireless interface 404 or the wired interface 406.

In certain embodiments, the processor 408 is a clock-driven electronicdevice that is configured to process input data according toinstructions stored in memory 410. The memory 410 is data storage thatmay be loaded with one or more software modules 414, which can beexecuted by the processor 408 to achieve certain tasks. In one example,a task might be for the zone player 400 to retrieve audio data fromanother zone player or a device on a network. In a second example, atask might be for the zone player 400 to send audio data to another zoneplayer or device on a network. In a third example, a task might be forthe zone player 400 to synchronize playback of audio with one or moreadditional zone players. In a fourth example, a task might be to pairthe zone player 400 with one or more zone players to create amulti-channel audio environment. In a fifth example, a task might be toshape the sound output from zone player 400 based on an orientation ofzone player 400, a different zone player, or a group of zone playersincluding zone player 400. Other tasks, such as those described herein,may be achieved via the one or more software modules 414 and theprocessor 408.

The audio processing component 412 may include one or moredigital-to-analog converters (DAC), an audio preprocessing component, anaudio enhancement component or a digital signal processor, and so on. Incertain embodiments, the audio that is retrieved via the networkinterface 402 is processed and/or intentionally altered by the audioprocessing component 412. Further, the audio processing component 412may produce analog audio signals. The processed analog audio signals arethen provided to the audio amplifier 416 for play back through speakers418. In addition, the audio processing component 412 may includenecessary circuitry to process analog or digital signals as inputs toplay from zone player 400, send to another zone player on a network, orboth play and send to another zone player on the network. An exampleinput includes a line-in connection (e.g., an auto-detecting 3.5 mmaudio line-in connection).

The audio amplifier 416 is a device that amplifies audio signals to alevel for driving one or more speakers 418. The one or more speakers 418may include an individual transducer (e.g., a “driver”) or a completespeaker system that includes an enclosure including one or more drivers.A particular driver might be a subwoofer (for low frequencies), amid-range driver (middle frequencies), and a tweeter (high frequencies).An enclosure might be sealed or ported.

A zone player 400 may also be referred to herein as a playback device.An example playback device includes a Sonos PLAY:5, which ismanufactured by Sonos, Inc. of Santa Barbara, Calif. The PLAY:5 is anexample zone player with a built-in amplifier and speakers. Inparticular, the PLAY:5 is a five-driver speaker system that includes twotweeters, two mid-range drivers, and one woofer. When playing audiocontent via the PLAY:5, the left audio data of a track is sent out ofthe left tweeter and left mid-range driver, the right audio data of atrack is sent out of the right tweeter and the right mid-range driver,and mono bass is sent out of the woofer. Further, both mid-range driversand both tweeters have the same equalization (or substantially the sameequalization). That is, they are both sent the same frequencies, justfrom different channels of audio. Audio from Internet radio stations,online music and video services, downloaded music, analog audio inputs,television, DVD, and so on may be played from a Sonos PLAY:5. While thePLAY:5 is an example of a zone player with speakers, it is understoodthat a zone player with speakers is not limited to one with a certainnumber of speakers (e.g., five speakers as in the PLAY:5), but rathercan contain one or more speakers. Further, a zone player may be part ofanother device, which might even serve a purpose different than audio(e.g., a lamp or television).

IV. Example Controller

Referring now to FIG. 5, there is shown an example controller 500, whichmay correspond to the controlling device 130 in FIG. 1. The controller500 may be used to facilitate the control of multi-media applications,automation and others in a system. In particular, the controller 500 isconfigured to facilitate a selection of a plurality of audio sourcesavailable on the network and enable control of one or more zone players(e.g., the zone players 102 to 124 in FIG. 1) through a wireless networkinterface 508. According to one embodiment, the wireless communicationsis based on an industry standard (e.g., infrared, radio, wirelessstandards IEEE 802.11a, 802.11b 802.11g, 802.11n, or 802.15). Further,when a particular audio is being accessed via the controller 500 orbeing played via a zone player, a picture (e.g., album art) or any otherdata, associated with the audio source may be transmitted from a zoneplayer or other electronic device to the controller 500 for display.

The controller 500 is provided with a screen 502 and an input interface514 that allows a user to interact with the controller 500, for example,to navigate a playlist of many multimedia items and to controloperations of one or more zone players. The screen 502 on the controller500 may be an LCD screen. The screen 500 communicates with and iscommanded by a screen driver 504 that is controlled by a microcontroller(e.g., a processor) 506. The memory 510 may be loaded with one or moreapplication modules 512 that can be executed by the microcontroller 506with or without a user input via the user interface 514 to achievecertain tasks. In one example, an application module 512 is configuredto facilitate grouping a number of selected zone players into a zonegroup and synchronizing the zone players for audio play back. In anotherexample, an application module 512 is configured to control the audiosounds (e.g., volume) of the zone players in a zone group. In operation,when the microcontroller 506 executes one or more of the applicationmodules 512, the screen driver 504 generates control signals to drivethe screen 502 to display an application specific user interfaceaccordingly.

The controller 500 includes a network interface 508 that facilitateswireless communication with a zone player. In one embodiment, thecommands such as volume control and audio playback synchronization aresent via the network interface 508. In another embodiment, a saved zonegroup configuration is transmitted between a zone player and acontroller via the network interface 508. The controller 500 may controlone or more zone players, such as 102 to 124 of FIG. 1. There may bemore than one controller for a particular system. Further, a controllermay be integrated into a zone player.

It should be noted that other network-enabled devices such as an iPhone,iPad or any other smart phone or network-enabled device (e.g., anetworked computer such as a PC or Mac) may be used as a controller tointeract or control zone players in a particular environment. Accordingto one embodiment, a software application or upgrade may be downloadedonto a network enabled device to perform the functions described herein.

In certain embodiments, a user may create a zone group including atleast two zone players from the controller 500. The zone players in thezone group may play audio in a synchronized fashion, such that all ofthe zone players in the zone group play back an identical audio sourceor a list of identical audio sources in a synchronized manner such thatno (or substantially no) audible delays or hiccups could be heard.Similarly, in one embodiment, when a user increases the audio volume ofthe group from the controller 500, the signals or data of increasing theaudio volume for the group are sent to one of the zone players andcauses other zone players in the group to be increased together involume.

A user via the controller 500 may group zone players into a zone groupby activating a “Link Zones” or “Add Zone” soft button, or de-grouping azone group by activating an “Unlink Zones” or “Drop Zone” button. Forexample, one mechanism for ‘joining’ zone players together for audioplay back is to link a number of zone players together to form a group.To link a number of zone players together, a user may manually link eachzone player or room one after the other. For example, assume that thereis a multi-zone system that includes the following zones: Bathroom,Bedroom, Den, Dining Room, Family Room, and Foyer.

In certain embodiments, a user can link any number of the six zoneplayers, for example, by starting with a single zone and then manuallylinking each zone to that zone.

In certain embodiments, a set of zones can be dynamically linkedtogether using a command to create a zone scene or theme (subsequent tofirst creating the zone scene). For instance, a “Morning” zone scenecommand may link the Bedroom, Office, and Kitchen zones together in oneaction. Without this single command, the user would need to manually andindividually link each zone. The single command might include a mouseclick, a double mouse click, a button press, a gesture, or some otherprogrammed action. Other kinds of zone scenes may be programmed.

In certain embodiments, a zone scene may be triggered based on time(e.g., such as an alarm clock function). For instance, a zone scene maybe set to apply at 8:00 am. The system could link appropriate zonesautomatically, set specific music to play, and then stop the music aftera defined duration. Although any particular zone may be triggered to anOn or Off state based on time, for example, a zone scene enables anyzones linked to the scene to play a predefined audio (e.g., a favorablesong, a predefined playlist) at a specific time and/or for a specificduration. If, for any reason, the scheduled music failed to be played(e.g., an empty playlist, no connection to a share, failed UPnP, noInternet connection for an Internet Radio station), a backup buzzer maybe programmed to sound. This buzzer may include a sound file that isstored in a zone player.

V. Maximizing System Performance

FIG. 6 shows an illustration of an example zone player 600 (or “player”)having a built-in amplifier and speakers 602. The zone player 600 mayreproduce a stereophonic signal, for example, such that the left channelaudio may be routed to the left speaker 604 and the right channel audiomay be routed to the right speaker 606. A monaural signal may be routedto the tweeter 608. Other frequency routing configurations are possiblein zone player 600 and/or with other types of zone players.

Let us assume that zone player 600 is designed to be a full-rangeplayer. Accordingly, zone player 600 is designed to reproduce as much ofthe audible frequency as possible in a given audio input signal, such aslow, mid, and high frequency signals. Zone player 600 may be placed in azone (e.g., an area or location) to wirelessly receive (or via a wire)an audio signal and play the full-range of that audio signal in thatarea. If so desired, a user may also pick up and move zone player 600 toa different zone and play the full-range of the audio signal in the newzone.

Such as described above, it is understood that zone player 600 contains,among other components, (1) speaker components, such as one or moreacoustic transducers (e.g., speakers 602), and (2) amplifier components,such as one or more amplifiers to power the speaker components. Givenits particular design, zone player 600 has a maximum sound pressurelevel (SPL) output. The maximum SPL output for zone player 600 may bebased on, for example, the cone area and excursion limits of the speakercomponents, in addition to the available amplifier power. In otherwords, the maximum SPL may be the highest output the zone player 600 canmanage short of damage, not exceeding a particular distortion level, orshort of an artificial limiter. Players of different sizes andcapabilities can exhibit a different SPL output.

In addition, the spectral content of an audio input signal can havesignificant affect on the excursion and heating of the speakercomponents and amplifier power being used by zone player 600. Forinstance, a wider bandwidth signal input into zone player 600 maygenerally push the zone player 600 to its limits at a lower SPL output.Reaching its limit at a lower SPL output is more likely given that zoneplayer 600 is currently configured to be a full-range player and isconfigured to play low frequency sound.

FIG. 7 shows zone player 600 from FIG. 6 combined with (bonded to)subwoofer 700. Subwoofer 700 is also player like zone player 600, butdesigned to reproduce low frequency sound. Subwoofer 700 may be added tothe zone or area of zone player 600 to play the lower frequencycomponents while zone player 600 plays the midrange to higher frequencycomponents. Alternatively, zone player 600 may be moved to or added tothe zone or area that contains subwoofer 700. Subwoofer 700 may bepaired to operate with zone player 600 via a wired or wireless network,such as described above. The process of adding subwoofer 700 to a zoneand/or pairing it to a player like zone player 600 can be performed by aset up wizard-like software program that guides the user through the setup process. For example, the subwoofer 700 may be plugged into astandard wall outlet for electrical power and then joined to zone player600 wirelessly or wired using a wireless controller, such as describedabove, and the set up wizard-like program. A similar process may beperformed to add (or bond) zone player 600 to subwoofer 700.

In some embodiments, once subwoofer 700 is added by the user to thesystem, zone player 600 and subwoofer 700 may each store an updatedstate variable that indicates the two have been set up to play audiotogether. For example, zone player 600 knows that it is paired withsubwoofer 700 based on its stored state variable. Similarly, subwoofer700 knows that it is paired with zone player 600 based on its storedstate variable.

In some embodiments, only zone player 600 contains an updated statevariable that identifies it has been paired with subwoofer 700, andtherefore zone player 600 may pass certain kinds of information tosubwoofer 700 over the network connection, like crossover filtercharacteristics (e.g., frequency and Q) to subwoofer 700 in order tooptimize the system performance based on the parameters of zone player600, subwoofer 700, or both zone player 600 and subwoofer 700. In someembodiments, the opposite may be true where it is subwoofer 700, insteadof zone player 600, which contains the updated state variable.

In some embodiments, zone player 600 may be configured to send the lowerfrequency signal to subwoofer 700 over the network connection, andtherefore subwoofer 700 may not need to update its configuration. Insome embodiments, the opposite may be true where it is subwoofer 700that sends the midrange and higher frequency signal to zone player 600,and therefore zone player 600 may not need to update its configuration.In some embodiments, the full-frequency signal is received at both zoneplayer 600 and subwoofer 700, and each device (e.g., zone player 600 andsubwoofer 700) filters the full-frequency signal according to itsplayback capabilities and/or settings.

When subwoofer 700 is configured for use with a full-range player, suchas zone player 600, the zone player 600 automatically makes adjustmentsto its settings to optimize performance. The adjustments are madeautomatically by the system and responsive to pairing such players,usually at the time of setting up the system. In one embodiment, thecrossover filter characteristics (e.g., frequency and Q) are determinedautomatically based on the parameters of zone player 600 and subwoofer700. In another embodiment, a time delay is determined and added to theaudio output of zone player 600, subwoofer 700, or both zone player 600and subwoofer 700. The time delay can provide improved synchronous timearrival of signals sent out from zone player 600 and subwoofer 700. Inanother embodiment, upmixing is automatically enabled for content thatdoes not natively support the configuration (e.g., stereo content can beupmixed to 2.1 to support the subwoofer). In another embodiment, adynamic range compressor or limiter function may be disabled. In yetanother embodiment, the amplifier gain for zone player 600 isautomatically increased. Particularly, a high-pass filter is applied tothe input audio signal going to zone player 600, so that the lowerfrequency sound can be sent over the wired or wireless network to beplayed by subwoofer 700. Zone player 600 is no longer configured to be afull-range player, but instead is configured to play midrange and highfrequency aspects of the audio signal. As such, there will be a smalleramount of excursion required of the low frequency speaker components andthe maximum SPL capability of zone player 600 can be greater. To takeadvantage of the potential increase in output capability, the gain forzone player 600 is automatically increased. In some embodiments, the newgain value is stored at zone player 600.

Additionally, in some embodiments, when subwoofer 700 is configured foruse with a full-range player, such as zone player 600, the subwoofer 700automatically makes one or more adjustments to optimize performance. Theadjustments are made automatically and responsive to pairing thesubwoofer 700 to another player. Particularly, in some embodiments, thecrossover filter characteristics (e.g., frequency and Q) may bedetermined based on the parameters of the pair player or players. Insome embodiments, a time delay may be determined. In some embodiments,the gain may be adjusted to optimize subwoofer performance.

The example above illustrates a number of advantages that may apply toone or more of the above embodiments. First, a zone that contains atleast one player is optimized for its current configuration, and suchconfiguration is automatically adjusted when an additional player, suchas a subwoofer is added to the zone. An adjustment might include, forexample, a crossover adjustment, an EQ adjustment, a timing delayadjustment, and a gain adjustment to play louder. As such, each part ofthe zone, and the zone as a whole, is optimized for better performance.Second, by reducing the low frequency output of a player, the softwarecan make an automatic adjustment to its gain and play louder (e.g., upto 3 dB in some embodiments, or more depending on the system). Third,pairing between two or more players can be automatically optimized basedon the parameters of the players themselves. Such parameters are madeknown, for example, during the set up process. Fourth, the system isoptimized based on its current configuration. For example, a zone may beoptimized if it only includes a full-range single player, a full-rangesingle player with a subwoofer, a stereo pair between two players, astereo pair between two players and a subwoofer, a multi-channel pairingbetween three or more players as in home theater, and so on. Suchoptimization may be triggered at set up of the zone.

Furthermore, it is understood that the above example is not limited tothe addition of a subwoofer or to a full-range player, but is applicablefor all players that can be used to amplify and reproduce a portion ofthe full audio content (even players without a speaker, such as theSonos CONNECT:AMP product may benefit from the technology describedherein). For example, if a zone includes a first player that is designedto play mid and high frequencies and it is paired with a second playerthat is designed to play mid frequencies, then the described technologymay be used to play only the high frequencies from the first player andincrease its SPL output by an automatic gain adjustment, for example.

In some embodiments, a person using a product without an amp, like theSonos CONNECT product, may also benefit from the described technologyif, for example, the amplifier that amplifiers the signal output of theproduct is configured to receive and/or use adjustable gain parameters.As such, it is not required that the various components that perform thedescribed technology be contained in a single product or device (e.g.,amplifier and speakers are not required to be a part of the sameproduct), but rather the various components may be interconnected insuch a way so as to be considered a “player” such as described herein tointelligently increase the loudness of the player. An exampleinterconnected system may include a Sonos CONNECT product wired to anA/V receiver in which the amplifier of the A/V receiver is configured touse different gain parameters based on the setup or configuration of azone or zones in order to optimize the loudness of such system. Anotherexample interconnected system may include a Sonos CONNECT product wiredto an active speaker or speakers in which the amplifier contained withthe speaker(s) is able to use different gain a parameters based on thesetup or configuration of a zone or zones in order to optimize theloudness of such system.

FIG. 8 shows a flowchart illustrating a method 800 for dynamicallyadjusting a sound level of a first player when combined with a secondplayer. Method 800 includes adding a second player to a zone thatcontains at least one first player per block 802.

Block 802 may include pairing the two or more players such that theyplay audio in synchrony, but they play various portions of the audioincluding different frequency components of the signal. Initial pairingor bonding occurs during set up of the zone when the second player isadded to the zone. The second player may operate wirelessly to receivethe audio signal from the first player or from a different player in thezone or not in the zone. In some embodiments, both players receive theaudio content wirelessly.

Block 804 calls for adjusting the configuration of the first player. Insome embodiments, any of three actions can trigger the configuration ofthe player: zone players are bonded (e.g., paired) or removed from abonded zone, a configuration change is made in the user interface (e.g.,the user selects/deselects a “sub” option), and based on the content(e.g., the SPL of the midrange may be increased with 2.1 audio whichincludes stereo left and right channels and a low-frequency channel, butnot with just 2-channel audio which only includes stereo left and rightchannels). When the second player is added to the zone, for example, theconfiguration of the first player is automatically adjusted to optimizethe performance of the first player and the zone itself. In the exampledescribed above, the first player can be configured in different ways.One such way is by applying a high-pass filter to the input audio signalif, for example, the second player contains a subwoofer. With thehigh-pass filter being applied to the input audio signal of the firstplayer, the maximum SPL capability of the first player can be greaterbecause it no longer has to reproduce the lower frequency part of thesignal. To take advantage of the potential increase in outputcapability, the gain for the first player is automatically increased. Insome embodiments, the gain may be increased for one or more (or all)amplifiers in the first player if more than one amplifier is used. Insome embodiments, the gain may be increased only for those amplifiersthat power the speaker components whose burden has been reduced becauseof the addition of the second player.

In some embodiments, for example, a signal processing filter is appliedto an audio signal at the player. In alternative embodiments, thesignal-processing filter is applied by a device or component before thesignal reaches the player.

Block 806 calls for determining whether the new configuration of thefirst player allows an increase in SPL. In some embodiments, thisdetermination is made by the first player. It might be based on theapplication of a signal processing filter, the type of input signal, orsome other indication. In some embodiments, this determination is madeby another device and the result is sent to the first player.

Block 808 calls for increasing the gain of one or more amplifiers in thefirst player if the new configuration allows an increase in SPL. In someembodiments, the gain may be determined by the first player. In someembodiments, the gain may be determined by another device and then sentto the first player. The increase in gain may be noticed by a userthrough increased loudness of the first player or the loudness of thefirst and second player together, for example.

In some embodiments, the process includes determining in real-time thehigher gain parameter based on the portion of the range of audiofrequencies to be reproduced by the first player. For example, if thelower frequencies will be handled by the second player, then the gaincan go higher than if the second player handles a different range offrequencies.

In some embodiments, the higher gain parameter is defined prior to thedetermination that no more than the portion of the range of audiofrequencies is to be reproduced by the first player. In other words, thehigher gain parameter is not determined in real-time.

Block 810 calls for saving the new settings. The first player reproducesits audio signal using the new, saved settings. The settings may changewhen the configuration is no longer optimized due to, for example,removal of the second player from the zone.

VI. Conclusion

The example embodiments described herein provide for numerous ways toincrease the sound level of a player when combined to play audio withanother player. Technology described herein may be used in anyapplication where optimized sound is desired, such as in residential orcommercial settings, motorized vehicles, boats, airplanes, and inoutdoor locations. Technology described herein may also be used incentralized networked audio systems instead of mesh network orpeer-to-peer type network systems.

For example, a device contains an amplifier for receiving an audiosignal containing a range of audio frequencies and amplifying, accordingto a gain parameter, the audio signal to be reproduced by at least onespeaker; and a processor for automatically increasing the gain parameterto a higher gain parameter responsive to a determination that no morethan a portion of the range of audio frequencies is to be reproduced bythe at least one speaker; wherein the amplifier amplifies, according tothe higher gain parameter, the audio signal containing no more than theportion of the range of audio frequencies to be reproduced by the atleast one speaker.

In another example, a method includes receiving an audio signalcontaining a range of audio frequencies; amplifying, according to a gainparameter, the audio signal to be reproduced by at least one speaker;automatically increasing the gain parameter to a higher gain parameterresponsive to a determination that no more than a portion of the rangeof audio frequencies is to be reproduced by the at least one speaker;and amplifying, according to the higher gain parameter, the audio signalcontaining no more than the portion of the range of audio frequencies tobe reproduced by the at least one speaker.

In yet another example, a computer readable storage medium includinginstructions for execution by a processor, the instructions, whenexecuted, cause the processor to implement a method comprising:receiving an audio signal containing a range of audio frequencies;enabling amplification, according to a gain parameter, the audio signalto be reproduced by at least one speaker; automatically increasing thegain parameter to a higher gain parameter responsive to a determinationthat no more than a portion of the range of audio frequencies is to bereproduced by the at least one speaker; and enabling amplification,according to the higher gain parameter, the audio signal containing nomore than the portion of the range of audio frequencies to be reproducedby the at least one speaker.

While example manners of implementing the example systems have beenillustrated in the accompanying Figures, one or more of the elements,processes and/or devices illustrated in the Figures may be combined,divided, re-arranged, omitted, eliminated and/or implemented in anyother way. Further, the examples illustrated in the Figures may beimplemented by hardware, software, firmware and/or any combination ofhardware, software and/or firmware. Thus, for example, the depictedelements may be implemented by one or more circuit(s), programmableprocessor(s), application specific integrated circuit(s) (ASIC(s)),programmable logic device(s) (PLD(s)) and/or field programmable logicdevice(s) (FPLD(s)), etc. When any of the apparatus or system claims ofthis patent are read to cover a purely software and/or firmwareimplementation, at least one of the example elements is hereby expresslydefined to include hardware and/or a tangible computer readable mediumsuch as a memory, DVD, CD, etc. storing the software and/or firmware.Further still, the example systems shown in the Figures may include oneor more elements, processes and/or devices in addition to, or insteadof, those illustrated in the accompanying Figures and/or may includemore than one of any or all of the illustrated elements, processes anddevices.

FIG. 8 is a flowchart representative of example machine-readableinstructions that may be executed to implement the example systems shownand described herein. In the example of FIG. 8, the machine-readableinstructions include a program for execution by a processor or microcontroller. The program may be embodied in software stored on a tangiblecomputer readable medium such as a CD-ROM, a floppy disk, a hard drive,a digital versatile disk (DVD), or a memory associated with a processor,but the entire program and/or parts thereof could alternatively beexecuted by a device other than the processor and/or embodied infirmware or dedicated hardware. Further, although the example program isdescribed with reference to the flowchart illustrated in FIG. 8, manyother methods of implementing the example systems may alternatively beused. For example, the order of execution of the blocks may be changed,and/or some of the blocks described may be changed, eliminated, orcombined.

As mentioned above, the example processes of FIG. 8 may be implementedusing coded instructions (e.g., computer readable instructions) storedon a tangible computer readable medium such as a hard disk drive, aflash memory, a read-only memory (ROM), a compact disk (CD), a digitalversatile disk (DVD), a cache, a random-access memory (RAM) and/or anyother storage media in which information is stored for any duration(e.g., for extended time periods, permanently, brief instances, fortemporarily buffering, and/or for caching of the information). As usedherein, the term tangible computer readable medium is expressly definedto include any type of computer readable storage and to excludepropagating signals. Additionally or alternatively, the exampleprocesses of FIG. 8 may be implemented using coded instructions (e.g.,computer readable instructions) stored on a non-transitory computerreadable medium such as a hard disk drive, a flash memory, a read-onlymemory, a compact disk, a digital versatile disk, a cache, arandom-access memory and/or any other storage media in which informationis stored for any duration (e.g., for extended time periods,permanently, brief instances, for temporarily buffering, and/or forcaching of the information). As used herein, the term non-transitorycomputer readable medium is expressly defined to include any type ofcomputer readable medium and to exclude propagating signals.

Various inventions have been described in sufficient detail with acertain degree of particularity. It is understood to those skilled inthe art that the present disclosure of embodiments has been made by wayof examples only and that numerous changes in the arrangement andcombination of parts can be resorted without departing from the spiritand scope of the present disclosure as claimed. While the embodimentsdiscussed herein can appear to include some limitations as to thepresentation of the information units, in terms of the format andarrangement, the embodiments have applicability well beyond suchembodiment, which can be appreciated by those skilled in the art.Accordingly, the scope of the present disclosure is defined by theappended claims rather than the forgoing description of embodiments.

We claim:
 1. Tangible, non-transitory computer-readable medium havingstored thereon instructions that, when executed by one or moreprocessors of a first playback device, cause the first playback deviceto perform functions comprising: entering a playback zone with a secondplayback device, wherein entering the playback zone comprises:determining a first maximum sound pressure level (SPL) capability of thefirst playback device while in the playback zone based on (i) an outputfrequency characteristic of the first playback device, and (ii) anoutput frequency range characteristic of the second playback device; anddetermining a first gain parameter for the first playback device whilein the playback zone based on the first maximum SPL capability; afterentering the playback zone, receiving a first audio signal comprising afirst audio frequency channel corresponding to the output frequencyrange of the second playback device and a second audio frequency channeldifferent from the first audio frequency channel; based on receiving thefirst audio signal (i) applying the first gain parameter to the secondaudio frequency channel of the first audio signal when playing the firstaudio frequency channel, and (ii) transmitting the first audio frequencychannel of the first audio signal to the second playback device forplayback by the second playback device in synchrony with playback of thefirst audio frequency portion by the first playback device; leaving theplayback zone such that the first playback zone is no longer in aplayback zone with the second playback device, wherein leaving theplayback zone comprises: determining a second maximum SPL capability ofthe first playback device based on the output frequency characteristicof the first playback device, wherein the second maximum SPL capabilityis lower than the first maximum SPL capability; and determining a secondgain parameter for the first playback device based on the second maximumSPL capability; after leaving the playback zone, receiving a secondaudio signal; and based on receiving the second audio signal, applyingthe second gain parameter to the second audio signal when playing thesecond audio signal.
 2. The tangible, non-transitory computer-readablemedium of claim 1, wherein the second audio signal is the same as thefirst audio signal.
 3. The tangible, non-transitory computer-readablemedium of claim 1, wherein the second audio signal comprises first audiofrequency channel and a second frequency channel different from thefirst audio frequency channel, and wherein applying the second gainparameter to the second audio signal when playing the second audiosignal comprises applying the second gain parameter to both the firstaudio frequency channel and the second audio frequency channel.
 4. Thetangible, non-transitory computer-readable medium of claim 1, whereinthe first playback device is a full-range playback device and the secondplayback device is a subwoofer device.
 5. The tangible, non-transitorycomputer-readable medium of claim 1, wherein the first playback devicecomprises a plurality of transducers, and wherein determining the firstSPL capability of the first playback device comprises determining thefirst SPL capability further based on characteristics of each of theplurality of transducers.
 6. The tangible, non-transitorycomputer-readable medium of claim 1, wherein the playback zone furthercomprises a third playback device, and wherein leaving the playback zonefurther comprises determining the second maximum SPL capability of thefirst playback device based further on an output frequencycharacteristic of the third playback device.
 7. The tangible,non-transitory computer-readable medium of claim 1, wherein transmittingthe first audio frequency channel of the first audio signal to thesecond playback device comprises transmitting the first audio frequencychannel of the first audio signal to the second playback device via awireless connection.
 8. The tangible, non-transitory computer-readablemedium of claim 1, wherein the functions further comprise: prior toentering the playback zone, receiving via a wireless connection from acontroller device, a command to form the playback zone, wherein thecommand identifies the first playback device and the second playbackdevice, and wherein entering the playback zone comprises entering theplayback zone in response to receiving the command.
 9. The tangible,non-transitory computer-readable medium of claim 1, wherein receivingthe first audio signal comprises: receiving via a wireless connectionfrom a controller device, data indicating a network address from whichthe first audio signal is to be retrieved; and receiving the first audiosignal from the network address.
 10. A first playback device comprising:one or more processors; and tangible, non-transitory computer-readablemedium having stored thereon instructions that, when executed by the oneor more processors of a first playback device, cause the first playbackdevice to perform functions comprising: entering a playback zone with asecond playback device, wherein entering the playback zone comprises:determining a first maximum sound pressure level (SPL) capability of thefirst playback device while in the playback zone based on (i) an outputfrequency characteristic of the first playback device, and (ii) anoutput frequency range characteristic of the second playback device; anddetermining a first gain parameter for the first playback device whilein the playback zone based on the first maximum SPL capability; afterentering the playback zone, receiving a first audio signal comprising afirst audio frequency channel corresponding to the output frequencyrange of the second playback device and a second audio frequency channeldifferent from the first audio frequency channel; based on receiving thefirst audio signal (i) applying the first gain parameter to the secondaudio frequency channel of the first audio signal when playing the firstaudio frequency channel, and (ii) transmitting the first audio frequencychannel of the first audio signal to the second playback device forplayback by the second playback device in synchrony with playback of thefirst audio frequency portion by the first playback device; leaving theplayback zone such that the first playback zone is no longer in aplayback zone with the second playback device, wherein leaving theplayback zone comprises: determining a second maximum SPL capability ofthe first playback device based on the output frequency characteristicof the first playback device, wherein the second maximum SPL capabilityis lower than the first maximum SPL capability; and determining a secondgain parameter for the first playback device based on the second maximumSPL capability; after leaving the playback zone, receiving a secondaudio signal; and based on receiving the second audio signal, applyingthe second gain parameter to the second audio signal when playing thesecond audio signal.
 11. The first playback device of claim 10, whereinthe second audio signal is the same as the first audio signal.
 12. Thefirst playback device of claim 10, wherein the second audio signalcomprises first audio frequency channel and a second frequency channeldifferent from the first audio frequency channel, and wherein applyingthe second gain parameter to the second audio signal when playing thesecond audio signal comprises applying the second gain parameter to boththe first audio frequency channel and the second audio frequencychannel.
 13. The first playback device of claim 10, wherein the firstplayback device is a full-range playback device and the second playbackdevice is a subwoofer device.
 14. The first playback device of claim 10,wherein the first playback device comprises a plurality of transducers,and wherein determining the first SPL capability of the first playbackdevice comprises determining the first SPL capability further based oncharacteristics of each of the plurality of transducers.
 15. The firstplayback device of claim 10, wherein the playback zone further comprisesa third playback device, and wherein leaving the playback zone furthercomprises determining the second maximum SPL capability of the firstplayback device based further on an output frequency characteristic ofthe third playback device.
 16. The first playback device of claim 10,wherein transmitting the first audio frequency channel of the firstaudio signal to the second playback device comprises transmitting thefirst audio frequency channel of the first audio signal to the secondplayback device via a wireless connection.
 17. A method comprising:entering, by a first playback device, a playback zone with a secondplayback device, wherein entering the playback zone comprises:determining, by the first playback device, a first maximum soundpressure level (SPL) capability of the first playback device while inthe playback zone based on (i) an output frequency characteristic of thefirst playback device, and (ii) an output frequency range characteristicof the second playback device; and determining, by the first playbackdevice, a first gain parameter for the first playback device while inthe playback zone based on the first maximum SPL capability; afterentering the playback zone, receiving, by the first playback device, afirst audio signal comprising a first audio frequency channelcorresponding to the output frequency range of the second playbackdevice and a second audio frequency channel different from the firstaudio frequency channel; based on receiving the first audio signal (i)applying, by the first playback device, the first gain parameter to thesecond audio frequency channel of the first audio signal when playingthe first audio frequency channel, and (ii) transmitting, by the firstplayback device, the first audio frequency channel of the first audiosignal to the second playback device for playback by the second playbackdevice in synchrony with playback of the first audio frequency portionby the first playback device; leaving, by the first playback device, theplayback zone such that the first playback zone is no longer in aplayback zone with the second playback device, wherein leaving theplayback zone comprises: determining, by the first playback device, asecond maximum SPL capability of the first playback device based on theoutput frequency characteristic of the first playback device, whereinthe second maximum SPL capability is lower than the first maximum SPLcapability; and determining, by the first playback device, a second gainparameter for the first playback device based on the second maximum SPLcapability; after leaving the playback zone, receiving, by the firstplayback device, a second audio signal; and based on receiving thesecond audio signal, applying, by the first playback device, the secondgain parameter to the second audio signal when playing the second audiosignal.
 18. The method of claim 17, wherein the second audio signalcomprises first audio frequency channel and a second frequency channeldifferent from the first audio frequency channel, and wherein applying,by the first playback device, the second gain parameter to the secondaudio signal when playing the second audio signal comprises applying, bythe first playback device, the second gain parameter to both the firstaudio frequency channel and the second audio frequency channel.
 19. Themethod of claim 17, wherein the first playback device is a full-rangeplayback device and the second playback device is a subwoofer device.20. The method of claim 17, wherein the playback zone further comprisesa third playback device, and wherein leaving, by the first playbackdevice, the playback zone further comprises determining, by the firstplayback device, the second maximum SPL capability of the first playbackdevice based further on an output frequency characteristic of the thirdplayback device.